EP0589405A1 - Carburettor needle valve adjustment limiter cap - Google Patents
Carburettor needle valve adjustment limiter cap Download PDFInfo
- Publication number
- EP0589405A1 EP0589405A1 EP93115159A EP93115159A EP0589405A1 EP 0589405 A1 EP0589405 A1 EP 0589405A1 EP 93115159 A EP93115159 A EP 93115159A EP 93115159 A EP93115159 A EP 93115159A EP 0589405 A1 EP0589405 A1 EP 0589405A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- shank
- cap
- valve
- carburetor
- arm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000446 fuel Substances 0.000 claims abstract description 46
- 230000000717 retained effect Effects 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 10
- 230000000295 complement effect Effects 0.000 claims description 6
- 239000004033 plastic Substances 0.000 claims description 6
- 229920003023 plastic Polymers 0.000 claims description 6
- 238000012360 testing method Methods 0.000 claims description 5
- 239000004677 Nylon Substances 0.000 claims description 4
- 229920001778 nylon Polymers 0.000 claims description 4
- 238000010276 construction Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 238000003780 insertion Methods 0.000 description 4
- 230000037431 insertion Effects 0.000 description 4
- 238000013021 overheating Methods 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229920004943 Delrin® Polymers 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- 229920006068 Minlon® Polymers 0.000 description 1
- 229920006102 Zytel® Polymers 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B63/00—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices
- F02B63/02—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for hand-held tools
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M3/00—Idling devices for carburettors
- F02M3/08—Other details of idling devices
- F02M3/10—Fuel metering pins; Nozzles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B41/00—Measures against loss of bolts, nuts, or pins; Measures against unauthorised operation of bolts, nuts or pins
- F16B41/005—Measures against unauthorised operation of bolts, nuts or pins
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B1/00—Engines characterised by fuel-air mixture compression
- F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
- F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M3/00—Idling devices for carburettors
- F02M3/08—Other details of idling devices
- F02M3/10—Fuel metering pins; Nozzles
- F02M2003/105—Needle adjustment limiter caps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- F05C2201/00—Metals
- F05C2201/02—Light metals
- F05C2201/021—Aluminium
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B37/00—Nuts or like thread-engaging members
- F16B37/14—Cap nuts; Nut caps or bolt caps
Definitions
- This invention relates to carburetors for internal combustion engines and more particularly to a limiter of the rotational adjustment of a fuel flow metering valve of the carburetor.
- carburetor limiter caps have been used to restrict carburetor fuel flow metering valve adjustment to prevent the excessive emission of carbon monoxide and unburned hydrocarbons from internal combustion engines.
- limiters have been used with conventional float bowl carburetors to control automobile exhaust emissions. More recently their use has been extended to diaphragm-type carburetors in small engines simply to prevent gross misadjustment of fuel flow.
- future emissions regulations are expected to extend the role of limiter caps to control engine emissions.
- Fuel flow within a carburetor is commonly metered during no load or idle engine operation by a first "idle" needle valve and during part or full load operation by a second "main” needle valve.
- each valve has a threaded cylindrical body with an enlarged knurled head at one end and a conical or needle shaped valve control surface at the opposite end which is received within an opening in the carburetor body.
- each valve is rotatively adjusted to axially extend or retract the valve control surface within a fuel passage in the carburetor until optimum fuel flow through the passage is achieved. Pre-calibration of the carburetor on a flow test bench may be performed prior to being assembled to an engine.
- limiter caps generally consist of a cylindrical body having an opening at one end for axially receiving the valve head in tight fitting engagement to prevent removal and promote rotation of both in unison.
- a recess in the opposite end of the cap is provided to enable an adjustment tool to engage the valve directly or the cap alone to rotate both in unison to make fuel flow adjustments.
- Projecting radially outwardly from the cap body is an arm for abutting against a fixed stop extending from the carburetor to limit valve rotation.
- Stop members such as an integrally cast projection of the carburetor or the body of another cap press-fit on an adjacent needle valve may be used to limit valve and cap rotation and hence adjustment.
- Japanese Patent Publication Jitsuko Sho 61-13455 discloses a hollow cylindrical collar limiter which has an outwardly extending arm for abutting directly against the head of an adjacent valve to limit adjustment.
- a two-stroke engine is sold with the adjustment range incorrectly set, subsequent user adjustment could increase emissions or deprive the engine of lubrication entrained in the fuel flow leading to overheating or even catastrophic failure.
- a user or operator of the power tool may lack the necessary range of fuel flow adjustment to keep the engine efficiently operating under the full range of temperature, humidity, altitude or other engine operating conditions which may be encountered.
- a cap and method for limiting the range of adjustment of a fuel flow metering valve in a carburetor has a body with a passage for telescopically axially receiving the head end of a shank of the metering valve therein. At the free end, the cap may have a face with a recess or opening therein for receiving an adjustment tool to rotate the cap, valve or both.
- An arm projects generally radially outwardly from the body to abut against a stop carried by or operably associated with the carburetor to limit valve rotation and hence adjustment.
- the cap has a retainer which retains the cap on the valve shank in a first position while allowing the cap to freely rotate relative to the valve.
- the cap is axially movable on the shank to a second position where a portion in the passage firmly engages the shank so that the cap and valve rotate only in unison to thereby limit adjustment of the valve by the arm engaging a stop.
- the cap is movable to a third position in which a drive portion releasably engages the shank for rotating the shank to adjust the valve before the cap is moved to the second position to limit further adjustment of the valve.
- the cap is locked in the second position to prevent removal of the cap from the shank to thereby insure continuous or tamper proof limiting of further adjustment of the valve.
- a cam portion in the passage facilitates movement of the cap to the second position.
- the cap In typical use, the cap is pressed onto the valve shank to a first position where it is retained on the shank and can rotate freely relative to the valve. On the shank, it may be moved from this position to releasably engage the valve for adjusting fuel flow.
- the limiter arm is angularly or circumferentially positioned on the valve to provide the desired limits of user fuel flow adjustment. Once the arm is properly oriented, the cap is further pressed axially inwardly to a second position securing the cap to the valve in tight engagement therewith so the cap and valve can rotate only in unison. Any subsequent rotational adjustment of the valve is limited in either direction by the limiter arm striking a stop carried by or operably associated with the carburetor.
- the cap can be circumferentially or angularly prepositioned relative to the adjusted shank to provide the desired high or low limit of user fuel flow adjustment by cooperating orienting means which are preferably in the form of a detent, web or spring associated with the cap. If desired, to prevent an end user from tampering with the needle valve and cap, they can be encircled by a shroud carried by the carburetor body.
- An object of the limiter cap of this invention is to restrict adjustment of a valve to prevent excessive engine exhaust emissions and engine overheating or failure.
- Another object is to facilitate quick and easy assembly of the cap to a needle valve of a carburetor body and final calibration of the carburetor while operating on an engine without requiring the removal of the grommet and engine shroud after final carburetor calibration.
- this limiter cap may be installed after initial calibration of an assembled carburetor on a flow test bench and prior to performing final calibration of the carburetor on an engine.
- a further object of the present invention is that it allows assembly of the limiter cap onto a needle valve of the carburetor to enable rotational adjustment of each valve during carburetor calibration, simple and accurate positioning of the arm of each cap relative to the final adjusted position of the valve and carburetor stops, and easy assembly of the cap into secure locking engagement with the valve to allow rotation of the cap and valve only in unison while limiting rotational adjustment of the valve in either direction.
- Another object of this cap is to allow limited fuel flow adjustment to enable a user of an engine powered tool to adequately adjust carburetor performance to fine tune engine operation under a variety of operating conditions while preventing fuel flow overadjustment possibly causing excessive exhaust gas emissions or engine overheating.
- a still further advantage of this invention is that it allows quick and easy limiter arm orientation when mounted in a freely rotating position on the valve to expediently, yet accurately, fix the allowable range of valve rotation.
- FIGS. 1 & 1A illustrate a typical assembly of a hand-held power tool 30 such as a hedge trimmer with a two-stroke gasoline engine 32 having a carburetor 34 with idle 36 and main 38 needle valves and limiter caps 40, 42 of this invention.
- the idle 36 and main 38 valves meter fuel flow during low speed and high speed engine operation respectively.
- the carburetor 34 has an air inlet 44 attached to an air cleaner 46 and an outlet 48 in communication with an intake manifold 50 of the engine 32.
- the engine 32 and carburetor 34 are enclosed by a housing or shroud 52 with a grommet 54 having a pair of access openings 56 axially aligned with each cap 40, 42 to enable limited valve adjustment while preventing tampering with or removal of either cap.
- each valve 36, 38 has an elongated generally cylindrical shank 60 with a head 62 at one end and a generally conical valve control surface 64 at the other end.
- the shank 60 has a plurality of threads 66 about its outer periphery to engage with complementary threads (not shown) within the carburetor body to enable secure insertion of the valve 36 therein and axial adjustment of the needle valve 36 within a fuel flow passage.
- a recess or slot 68 is provided in the free end of the valve 36 for receiving an adjustment tool, such as the blade of a screwdriver, for facilitating rotational adjustment of the valve 36.
- an adjustment tool such as the blade of a screwdriver
- a plurality of axial ridges or knurls 70 in the outer peripheral surface of the head 62 may be engaged by a tool or manually for adjustment. Unintentional valve rotation during engine vibration is prevented by a spring 72 received over the valve shank 60 and disposed between the carburetor body 34 and a flange 74 on the valve shank 60 adjacent the head 62.
- each needle valve 36, 38 is separated into a first segment or shoulder 76 at the end of the valve and a second segment 78 adjacent the spring retaining flange 74 by a circumferentially continuous groove 80.
- the head segments 76, 78 may also be knurled with axially extending flutes.
- Each cap 40, 42 has a body 82 with an arm 84 projecting therefrom for limiting valve rotation and hence adjustment. The location of the arm 84, 84' on the body is the only difference between these caps.
- the body 82 has a passage 86 therein.
- Portions within the passage 86 enable the cap 40 to be carried on a valve 36 in a freely rotating first position during assembly and limiter arm 84 orientation, in a second position securing the cap 40 to the valve 36 to limit adjustment and maintain emissions calibration, and in a third position to releasably drivingly engage the valve 36 to perform fuel flow adjustment.
- the body 82 also has a generally slotted recess 88 in the face of the free end of the cap 40 for receiving an adjustment tool therein.
- the limiter arm 84 is an arcuate flanged projection which extends generally radially outwardly from the body 82 for abutting against a stop 90 carried by or operably associated with the carburetor to limit rotation to less than a complete revolution.
- the stop may be an adjacent valve shank, a cap mounted thereon (FIG. 7) 90, a fixed stop 90' projecting from the carburetor body (FIG. 8), a projection extending from the housing 52, grommet 54, or engine 32 (not shown), or the like.
- the arm 84 is set axially back from the cap face to allow adjustment without the surrounding grommet 54 objectionably interfering with the arm 84.
- the arm 84 may be located anywhere along the axial length of the body 82.
- the angle subtended by the flange arm 84 is sufficient to limit the extent to which the valve 36 can be rotated to fine tune the engine, or to conform with any required emissions regulation.
- the arm 84 may have a locator indention 92 in its outer periphery to facilitate its use in an automatic cap feeding device.
- the cap 40 may be mounted on the valve 36 in a driving position with a first portion or circumferentially continuous rib 94 within the passage 86 adjacent the opening releasably drivingly engaging the knurled head 62.
- the cap 40 and hence the valve 36 can be rotated in unison to perform initial calibration adjustments.
- the mouth of the passage 86 has a chamfer 96 to facilitate entry of the valve head 62 into the rib 94.
- the cap 40 is first placed on the head 62 in the retainer position shown in FIG. 5 which allows the cap 40 to rotate freely with respect to the valve 36 while retained thereon.
- the first segment 76 of the valve head 62 is received in a circumferentially continuous recess 98 in the passage 86 with sufficient clearance to enable free rotation.
- the rib 94 of the passage 86 and the shoulder 76 of the valve 36 have an interference fit to retard removal from this freely rotating position.
- the cap 40 can be pushed slightly axially inwardly to engage the chamfer 96 with the second head segment 78 to adjust the valve 36 by rotating the cap 40.
- the chamfer 102 and portion of the first rib 94 adjacent chamfer 96 within the cap passage 86 may also releasably engage the knurled first 76 and second 78 head segments respectively.
- the cap 40 may be pressed further axially onto the valve 36 so the head 62 frictionally engages and/or intermeshes with a circumferentially continuous rib in a third portion 100 of the passage 86.
- the head 62 frictionally engages and/or intermeshes with a circumferentially continuous rib in a third portion 100 of the passage 86.
- the rib 100 has an interference fit and when received in this position the material of the inner peripheral surfaces of the first 94 and third 100 portions deform around the knurls of the second head segment 78 to securely couple together the valve 36 and cap 40 for simultaneous rotation and to resist removal of the cap 40.
- An interference fit between an adjacent shoulder of a circumferentially continuous recess 104 at the end of the passage 86 and the adjacent edge of the first segment 76 of the head 62 securely locks the cap 40 to the valve 36 further preventing removal.
- FIGS. 19-21 illustrate a protective shroud 150 for the needle valves 36 & 38 and caps 40 & 42 carried by the carburetor 48.
- the shroud 150 is generally in the shape of a basket or cup with a bottom wall 152, a preferably integral sidewall 154 lying closely adjacent the limiter caps, and an open end 156 opening generally axially of the limiter caps to provide access for adjustment thereof.
- the sidewall 154 of the shroud extends axially over and beyond the caps and lies closely adjacent to the periphery of the caps.
- the sidewall is of generally oval configuration with opposed semi-circular portions 158 inter-connected by parallel portions 160 which are spaced from and lie closely adjacent to the periphery of the limiter caps.
- the bottom wall 152 has clearance holes 162 through which the shanks of the valves extend and in assembly is yieldably urged in firm engagement with a support surface 164 of the carburetor body by the compression springs 72.
- the shroud 150 is a one-piece metal stamping or a molded plastic part.
- FIG. 22 illustrates a modified form of the shroud and carburetor assembly in which a shroud 150' is formed as an integral part of the body of the carburetor 34.
- the shroud 150' and carburetor are die cast as one part of a low melting temperature metal such as aluminum.
- FIGS. 9-12 illustrate a second form of a needle valve 36' and a cap 40'.
- the needle valve 36' is essentially the same as needle 36 except that the first head segment 76' has a slot 68 therein for receiving the blade of a tool, such as a screwdriver, to rotate the valve 36' and a peripheral cam surface 106.
- a tool such as a screwdriver
- the body 82 has an access hole 108 through the free end thereof.
- the cap 40' has essentially the same construction as cap 40.
- the cap 40' can be disposed in a first position on the needle valve 36' where it is retained thereon while being freely rotatable relative to the valve 36' so that it does not drivingly engage it.
- the cap 36' can be pushed slightly axially inward of this position, either manually or with a tool engaging slot 88' or an arcuate relief indentation 89 in flange 84, to releasably drivingly engage the chamfer surface 96 with the adjacent end of the second head segment 78 to drivingly turn the valve 36' by rotating the cap 40'.
- a portion of the first rib 94 adjacent the chamfer 96 may also releasably engage the second head segment 78 to facilitate adjusting the valve 36'.
- the cap 40' When released, the cap 40' will normally return to the retained position (FIG. 9) where it can freely rotate relative to the valve 36'.
- the valve can be directly adjusted by inserting a tool through bore 108 and engaging slot 68. As shown in FIG. 12, the cap 40' can be pressed further axially onto the valve 36' to a second position where the valve 36' and cap 40' are securely coupled together to limit rotation of the valve 36'.
- fine adjustment may be made by using a tool to engage slot 88' or indention 89 in the cap or slot 68 in the first segment 76' of the valve head 62'.
- FIGS. 13-15 illustrate a third form of the invention with needle valve 36' and cap 40. Since the cap 40 has a closed free end with a driving slot 88 therein, once the cap 40 is received on the needle valve 36', the slot 88 in the head 62' of the valve 36' cannot be directly engaged to rotate the valve 36'.
- the cap 40 in a first position the cap 40 is retained on the valve 36' while being freely rotatable relative to the valve 36' and can be pushed slightly axially inward of this position to engage the chamfered portion 96 with the head 62' to drivingly turn the valve 36' by rotating the cap 40. As shown in FIG. 15, the cap 40 can be pushed further axially onto the valve 36' to a second position to couple and secure the cap 40 and valve 36' for rotation therewith to limit adjustment of the valve 36'.
- FIGS. 16-18 A fourth form of the invention is shown in FIGS. 16-18 with a needle valve 36'' and a cap 40''.
- the cap 40'' is releasably retained and freely rotates in a first position on the valve 36'' by the cooperation of a circumferentially continuous recess 98'' in the passage of the cap 40'' and a head 62'' on the free end of the valve 36''.
- the cap 40'' is retained on the head 62'' in the freely rotating position by the cooperation of the adjacent edge or shoulder of the recess 98'' which has a slight interference fit with the adjacent edge of the head 62''.
- the cap 40'' in a second position, is securely coupled to the valve 36'' by frictional or intermeshing engagement of the head 62'' with a third portion 100'' of the passage to limit adjustment of the valve 36''. Insertion of the head 62'' into the inner rib 100'' is facilitated by a chamfer 102'' at the entrance thereto.
- the cap 40'' can be releasably drivingly engaged with the head 62'' of the needle valve 36'' by pushing the shoulder of the first passage portion 94'' into engagement with the leading portion of the head 62''.
- the chamfer 96'' facilitates engaging the shoulder with the head 62''.
- a fifth form of the invention in shown in FIGS. 23-25 with limiter caps 110 and 112 received on idle and main needle valves 114 and 116.
- the basic construction and arrangement of the caps 110 and 112 is substantially the same as that of the caps 40' and 42'.
- they in accordance with another feature of this invention, to facilitate disposing the caps 110 & 112 in a predetermined relative circumferential or angular position with respect to the desired range of user adjustment of the needle valves (such as high end or low end of the range) before they are securely assembled in a limiter position on the valves, as shown in FIG. 25, they have cooperating detents 118 and 120 thereon.
- the detents project radially outwardly of the body of their cap and are axially disposed so that they overlap and abut when, as shown in FIG. 23, both of the caps are received in the first or retainer position on the valve shanks and, as shown in FIG. 25, the limiter arm 84 or 84' of each cap bears on the other cap. This ensures a predetermined orientation of each limiter cap relative to the adjusted position of its needle valve so that when, as shown in FIG. 24, the caps are assembled in the limiter position on the valve shanks, they are in a predetermined desired orientation (high end or low end) relative to the range of user adjustment they permit for each needle valve.
- each cap and its detent are molded in one piece of a somewhat resilient plastic material such as nylon.
- FIGS. 26-28 illustrate a suitable bit or tool 122 for engaging and turning the valves 114 & 116 when a limiter cap 110 & 112 is received thereon.
- the tool has a square shank 124 which merges into a conical tip 126 at one end. As shown in FIG. 23 in use, the tool is inserted through the cap and the tip 126 is disposed in a chamfered blind bore 128 in the head of the valve for generally axially aligning the tool therein.
- a pair of opposed side faces 130 of the shank of the tool are slidably received between the side faces 132 of the slot 68 in the head for driving engagement therewith to rotate the valve by rotating or turning the tool.
- FIG. 29 illustrates modified limiter caps 110', 112' having a thin interconnecting web 134 in lieu of the detents 118 and 120 of the limiters cap 110 and 112.
- limiter caps 110' & 112' are molded together along with the web 134 in one piece preferably of a plastic material.
- the caps interconnected by the web are installed on valves 114 and 116 initially in the retainer position and then after final adjustment of the valves are moved in unison to the limiter position. This orients the cap relative to the adjusted position of the valves in a manner similar to that of the detents 118 and 120 of the caps 110 and 112. Thereafter, when an end user initially rotates one of the caps, web 134 is broken and each needle valve can be adjusted within the predetermined range provided by the limiter caps.
- FIGS. 30-32 A seventh form of the invention is illustrated in FIGS. 30-32 in which a pair of limiter caps 140 & 140' are received on idle and main needle valves 114 & 116 and each disposed in a predetermined circumferential or angular orientation relative to its needle valve by the cooperation of a compression and torsion spring 142 therewith.
- the spring has at one end a radially inwardly projecting tang 144 which in assembly is received in the slot 68 in the head of the valve and at the other end an axially projecting tang 146 which in assembly is received in a complementary blind hole 148 in the end wall of the cap.
- the only difference between the caps 140 & 140' is the arcuate location of the holes 148 which are relatively diametrically opposed. However, if desired, the holes could be in the same location for both caps and the spring tangs 144 would be received in relatively opposite ends of the valve head slots 68.
- the cap When received in the first or retainer position on a valve, the cap can be disposed in any desired predetermined circumferential orientation relative to its valve by selecting and designing the desired circumferential or angular orientation of the spring tang 144 & 146 to each other and to the slot 68 in the valve and the hole 148 in the cap. For example, as shown in FIG. 32, these parameters can be selected and adjusted so that after any fine tuning adjustment of the valves, the caps will be oriented in the retainer position so that the limiter arm 84 or 84' of each cap bears on the body of the other cap when, as shown in FIG. 32, the caps are to be securely assembled in the limiter position on the valves.
- the caps may be pressed onto the valve 36 to a position where the first segment 76 of the valve head 62 engages with the rib 94 of the cap passage 86. While in this position, the valve 36 may be adjusted, such as during flow testing or final calibration. To adjust the valve 36, torque is applied to the cap 40 through an adjustment tool engaging the cap recess 88.
- the cap 40 is initially mounted to and carried by the valve 36 in the freely rotating retainer position.
- the cap 40 may be attached in this retainer position any time after flow testing so that the carburetor 34 may be shipped or other assembly operations performed without inadvertently disturbing the valve calibration.
- fine adjustment of fuel flow to tune an actual specific engine in operation into compliance with emissions requirements may be simply and easily achieved.
- the slotted cap face 88 is engaged by an adjustment tool and a sufficient axially inward force is applied against the cap 40 causing the first passage section 94 to releasably engage the knurled second segment 78 enabling rotation in unison. While engaged, the cap 40 and valve 36 may be rotated until engine exhaust emissions fall within the desired range. If the limiter arm 84 abuts against a stop 90 and more adjustment is needed, the applied force can be withdrawn releasing the cap 40 from frictional engagement and the arm 84 freely rotated away from the stop 90 without rotating the valve 36 to provide an additional range of adjustment.
- cap 40 may be used to ratchet the valve 36 in either direction to provide an unlimited range of adjustment.
- emissions calibration may also be performed at this assembly stage simply by directly engaging the valve 36, 36', 114 or 116 with an adjustment tool.
- the cap Before securing a cap to a valve, the cap (other than cap 110', 112') is freely rotated to easily and accurately orient the limiter arm 84 or 84' relative to the calibrated valve and stop member.
- the limiter arm position, arm flange width and stop configuration and position are selected, designed and constructed as will be apparent to skilled persons and need not be described in further detail.
- the caps 110 & 112, 110'& 112' and 140 & 140' may be readily circumferentially oriented relative to their completely calibrated valves, stop members and the desired allowable range of adjustment by the end user by their detents 118 & 120, web 132, or cooperating springs 142.
- the caps 110 and 112 may be so oriented by engagement of their arms and the detents 118 and 120, as shown in FIG. 25, so that if their needle valves have right-hand threads, the caps are oriented at the high end or max low rate of the desired range of adjustment by the end user.
- the same orientation is achieved for the caps 110'& 112' by the web 134 and for the caps 140 & 140' by cooperation by the springs 142.
- valve adjustment may be performed after final cap assembly if the allowable range of rotation is sufficient to properly calibrate fuel flow.
- valve (36, 36', 114 or 116) rotation in either direction is restricted by the arm 84 or 84' abutting with a stop 90 or 90' preventing emissions-violating overadjustment by an end user while enabling a sufficient adjustment range to fine tune engine performance in response to a wide range of operating conditions.
- the limiter caps are of one piece, unitary construction for simpleness and ease of manufacture, and are constructed from a generally homogeneous material such as Zytel® or Minlon®, nylon formulations which are both registered trademarks of E. I. Du Pont De Nemours and Company, a different nylon formulation, Delrin® (a POM thermoplastic) also a Du Pont material, or another high temperature thermoplastic material.
- a cap constructed of any of these materials is strong and resilient and able to deform around the knurls of the valve head to more positively frictionally secure the cap to the valve while resisting brittle fracture if tampered with.
- the caps could also be composed of a phenolic, polyurethane, polyacrylic, rubber or some other plastic material.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Control Of The Air-Fuel Ratio Of Carburetors (AREA)
- Lift Valve (AREA)
- Portable Nailing Machines And Staplers (AREA)
Abstract
Description
- This is a continuation-in-part of copending application Ser. No. 07/949,895, filed September 23, 1992, which issued into U.S. Patent No. 5,236,634.
- This invention relates to carburetors for internal combustion engines and more particularly to a limiter of the rotational adjustment of a fuel flow metering valve of the carburetor.
- In response to relatively recent federal and state "clean air" regulations, carburetor limiter caps have been used to restrict carburetor fuel flow metering valve adjustment to prevent the excessive emission of carbon monoxide and unburned hydrocarbons from internal combustion engines. Primarily, limiters have been used with conventional float bowl carburetors to control automobile exhaust emissions. More recently their use has been extended to diaphragm-type carburetors in small engines simply to prevent gross misadjustment of fuel flow. However, future emissions regulations are expected to extend the role of limiter caps to control engine emissions.
- Fuel flow within a carburetor is commonly metered during no load or idle engine operation by a first "idle" needle valve and during part or full load operation by a second "main" needle valve. Typically, each valve has a threaded cylindrical body with an enlarged knurled head at one end and a conical or needle shaped valve control surface at the opposite end which is received within an opening in the carburetor body. To calibrate fuel flow, each valve is rotatively adjusted to axially extend or retract the valve control surface within a fuel passage in the carburetor until optimum fuel flow through the passage is achieved. Pre-calibration of the carburetor on a flow test bench may be performed prior to being assembled to an engine. Subsequent overadjustment of fuel flow is prevented by affixing a limiter cap over the head of each valve. After assembly to an engine, it is customary to adjust the metering valves, if needed, to fine tune fuel flow to actual engine demand.
- These limiter caps generally consist of a cylindrical body having an opening at one end for axially receiving the valve head in tight fitting engagement to prevent removal and promote rotation of both in unison. A recess in the opposite end of the cap is provided to enable an adjustment tool to engage the valve directly or the cap alone to rotate both in unison to make fuel flow adjustments. Projecting radially outwardly from the cap body is an arm for abutting against a fixed stop extending from the carburetor to limit valve rotation. Representative limiter caps are described in U. S. Patents Charron 3,618,906 and Araki 5,055,238.
- Stop members such as an integrally cast projection of the carburetor or the body of another cap press-fit on an adjacent needle valve may be used to limit valve and cap rotation and hence adjustment. Similarly, Japanese Patent Publication Jitsuko Sho 61-13455, discloses a hollow cylindrical collar limiter which has an outwardly extending arm for abutting directly against the head of an adjacent valve to limit adjustment.
- Previous to the use of these limiting devices, fuel flow metering valves in carburetors were freely adjustable without limitation. At present, however, limiters have not been universally adopted for carburetors for small engine applications. Particularly, because of numerous difficulties, caps of conventional construction have not been used in applications, such as hand-held tools like weed trimmers, edgers, blowers, chain saws, and hedge trimmers, where carburetor access is restricted by an engine shroud enclosing the engine compartment.
- While access openings are provided in the shroud by a grommet to adjust each valve, they are not large enough to allow limiter cap installation after final calibration without removing the shroud. Further, limited accessibility adds to the difficulty of accurately orienting the arm of the cap with respect to the optimum valve position and the stop or stops of the carburetor to provide the appropriate range of adjustability. Removal and reorientation of the cap after calibration with the cap secured to the valve is impractical and time consuming as it would require the application of considerable force to remove the limiter possibly damaging the cap. Production time may also be lost if the shroud or grommet must be disassembled to gain sufficient access to the cap. Unfortunately, disturbing the valve in this manner to remove the cap would likely require recalibration before reinstalling the same or a different limiter cap.
- For example, if a two-stroke engine is sold with the adjustment range incorrectly set, subsequent user adjustment could increase emissions or deprive the engine of lubrication entrained in the fuel flow leading to overheating or even catastrophic failure. In any event, a user or operator of the power tool may lack the necessary range of fuel flow adjustment to keep the engine efficiently operating under the full range of temperature, humidity, altitude or other engine operating conditions which may be encountered.
- With or without an enclosure or shroud, assembly and proper orientation of these caps is difficult and requires considerable dexterity. If improperly oriented, its tamper proof construction virtually prevents removal without damaging the cap and disturbing the optimum fuel flow setting of the valve.
- A cap and method for limiting the range of adjustment of a fuel flow metering valve in a carburetor. The limiter cap has a body with a passage for telescopically axially receiving the head end of a shank of the metering valve therein. At the free end, the cap may have a face with a recess or opening therein for receiving an adjustment tool to rotate the cap, valve or both. An arm projects generally radially outwardly from the body to abut against a stop carried by or operably associated with the carburetor to limit valve rotation and hence adjustment.
- In the passage, the cap has a retainer which retains the cap on the valve shank in a first position while allowing the cap to freely rotate relative to the valve. The cap is axially movable on the shank to a second position where a portion in the passage firmly engages the shank so that the cap and valve rotate only in unison to thereby limit adjustment of the valve by the arm engaging a stop. Preferably, the cap is movable to a third position in which a drive portion releasably engages the shank for rotating the shank to adjust the valve before the cap is moved to the second position to limit further adjustment of the valve. Preferably, the cap is locked in the second position to prevent removal of the cap from the shank to thereby insure continuous or tamper proof limiting of further adjustment of the valve. Preferably, a cam portion in the passage facilitates movement of the cap to the second position.
- In typical use, the cap is pressed onto the valve shank to a first position where it is retained on the shank and can rotate freely relative to the valve. On the shank, it may be moved from this position to releasably engage the valve for adjusting fuel flow. After carburetor performance has been optimized, the limiter arm is angularly or circumferentially positioned on the valve to provide the desired limits of user fuel flow adjustment. Once the arm is properly oriented, the cap is further pressed axially inwardly to a second position securing the cap to the valve in tight engagement therewith so the cap and valve can rotate only in unison. Any subsequent rotational adjustment of the valve is limited in either direction by the limiter arm striking a stop carried by or operably associated with the carburetor.
- Preferably after carburetor performance has been optimized and before a cap is pressed axially inwardly to the second position in tight engagement with the valve shank, the cap can be circumferentially or angularly prepositioned relative to the adjusted shank to provide the desired high or low limit of user fuel flow adjustment by cooperating orienting means which are preferably in the form of a detent, web or spring associated with the cap. If desired, to prevent an end user from tampering with the needle valve and cap, they can be encircled by a shroud carried by the carburetor body.
- An object of the limiter cap of this invention is to restrict adjustment of a valve to prevent excessive engine exhaust emissions and engine overheating or failure.
- Another object is to facilitate quick and easy assembly of the cap to a needle valve of a carburetor body and final calibration of the carburetor while operating on an engine without requiring the removal of the grommet and engine shroud after final carburetor calibration.
- Another advantage is this limiter cap may be installed after initial calibration of an assembled carburetor on a flow test bench and prior to performing final calibration of the carburetor on an engine.
- A further object of the present invention is that it allows assembly of the limiter cap onto a needle valve of the carburetor to enable rotational adjustment of each valve during carburetor calibration, simple and accurate positioning of the arm of each cap relative to the final adjusted position of the valve and carburetor stops, and easy assembly of the cap into secure locking engagement with the valve to allow rotation of the cap and valve only in unison while limiting rotational adjustment of the valve in either direction.
- Another object of this cap is to allow limited fuel flow adjustment to enable a user of an engine powered tool to adequately adjust carburetor performance to fine tune engine operation under a variety of operating conditions while preventing fuel flow overadjustment possibly causing excessive exhaust gas emissions or engine overheating.
- A still further advantage of this invention is that it allows quick and easy limiter arm orientation when mounted in a freely rotating position on the valve to expediently, yet accurately, fix the allowable range of valve rotation.
- Another advantage is that the cap may be carried on the valve during assembly without dislodging or vibrating free. These and other objects, features and advantages of this invention will be apparent from the following detailed description and appended claims in which the invention is set forth together with sufficient details to enable persons skilled in the art to practice the invention all in connection with the best mode presently contemplated of the invention.
-
- FIG. 1 is a fragmentary perspective view of a hedge trimmer having a two-stroke engine with a carburetor with fuel flow metering needle valves and limiters of this invention;
- FIG. 1A is an exploded perspective view of the carburetor, main and idle needle valves, and limiter caps for each valve;
- FIG. 2 is an exploded side view of a needle valve and a cap in section of this invention;
- FIG. 3 is a front view of the cap;
- FIG. 4 is a sectional view of the cap assembled in a driving position on a head of the valve;
- FIG. 5 illustrates the cap assembled in a retainer position on the valve;
- FIG. 6 illustrates the cap secured in a limiter position on the valve;
- FIG. 7 is a perspective view of a carburetor assembly illustrating caps of this invention mounted on both the main and idle needle valves;
- FIG. 8 is a front view of a second carburetor configuration;
- FIG. 9 is a side sectional view of a second cap embodiment assembled in a retainer position on the valve;
- FIG. 10 is a front view of the second cap;
- FIG. 11 illustrates the second cap in a releasable driving position on the valve;
- FIG. 12 illustrates the second cap securely assembled in a limiter position on the valve;
- FIG. 13 is a side sectional view of a third cap embodiment assembled in a retainer position on a valve;
- FIG. 14 is a front view of the third cap;
- FIG. 15 illustrates the third cap securely assembled in a limiter position on the valve;
- FIG. 16 is a side sectional view of a fourth cap embodiment assembled in a driving position on the valve;
- FIG. 17 illustrates the fourth cap assembled in a retainer position on the valve;
- FIG. 18 shows the fourth cap securely assembled in a limiter position on the valve;
- FIG. 19 is a perspective view of a carburetor assembly with a separate shroud encircling the limiter caps and needle valves;
- FIG. 20 is a side view of the carburetor assembly of FIG. 19;
- FIG. 21 is a bottom view with portions broken away and in section of the carburetor assembly of FIG. 19;
- FIG. 22 is a fragmentary bottom view with portions broken away and in section of a modification of the shroud and carburetor assembly of FIG. 19;
- FIG. 23 is a fragmentary and sectional side view of a fifth cap embodiment assembled in a retainer position on the valve;
- FIG. 24 is a fragmentary and sectional side view of the fifth cap embodiment assembled in a limiter position on the valve;
- FIG. 25 is a fragmentary end view of the fifth cap embodiment;
- FIG. 25a is an enlarged fragmentary view of that portion of the limiter caps shown in FIG. 25 enclosed by the circle 25a;
- FIG. 26 is a side view of a tool for adjusting the needle valve of the fifth cap embodiment;
- FIG. 27 is a view of one end of the tool of FIG. 26;
- FIG. 28 is an end view of the other end of the tool of FIG. 26;
- FIG. 29 is a fragmentary end view of a sixth cap embodiment;
- FIG. 29a is an enlarged fragmentary view of that portion of the limiter caps shown in FIG. 29 enclosed by the circle 29a;
- FIG. 30 is a fragmentary and sectional side view of a seventh cap embodiment assembled in a retainer position on the valve;
- FIG. 31 is a fragmentary and sectional side view of the seventh cap embodiment assembled in a limiter position on the valve;
- FIG. 32 is a fragmentary end view of the seventh cap embodiment;
- FIG. 33 is a side view of a spring of the seventh cap embodiment; and
- FIG. 34 is an end view of the spring of FIG. 33.
- With reference to the drawings, FIGS. 1 & 1A illustrate a typical assembly of a hand-held
power tool 30 such as a hedge trimmer with a two-stroke gasoline engine 32 having acarburetor 34 with idle 36 and main 38 needle valves and limiter caps 40, 42 of this invention. The idle 36 and main 38 valves meter fuel flow during low speed and high speed engine operation respectively. - The
carburetor 34 has anair inlet 44 attached to anair cleaner 46 and anoutlet 48 in communication with anintake manifold 50 of theengine 32. Theengine 32 andcarburetor 34 are enclosed by a housing orshroud 52 with agrommet 54 having a pair ofaccess openings 56 axially aligned with eachcap - As shown in FIGS. 1A and 2, each
valve cylindrical shank 60 with ahead 62 at one end and a generally conicalvalve control surface 64 at the other end. Theshank 60 has a plurality ofthreads 66 about its outer periphery to engage with complementary threads (not shown) within the carburetor body to enable secure insertion of thevalve 36 therein and axial adjustment of theneedle valve 36 within a fuel flow passage. - Typically, a recess or
slot 68 is provided in the free end of thevalve 36 for receiving an adjustment tool, such as the blade of a screwdriver, for facilitating rotational adjustment of thevalve 36. Alternatively, a plurality of axial ridges orknurls 70 in the outer peripheral surface of thehead 62 may be engaged by a tool or manually for adjustment. Unintentional valve rotation during engine vibration is prevented by aspring 72 received over thevalve shank 60 and disposed between thecarburetor body 34 and aflange 74 on thevalve shank 60 adjacent thehead 62. - Preferably, the
head 62 of eachneedle valve shoulder 76 at the end of the valve and asecond segment 78 adjacent thespring retaining flange 74 by a circumferentiallycontinuous groove 80. Preferably, for firm engagement with the cap, thehead segments cap body 82 with anarm 84 projecting therefrom for limiting valve rotation and hence adjustment. The location of thearm 84, 84' on the body is the only difference between these caps. For axially telescoping thecap 40 over the end of avalve 36, thebody 82 has apassage 86 therein. Portions within thepassage 86 enable thecap 40 to be carried on avalve 36 in a freely rotating first position during assembly andlimiter arm 84 orientation, in a second position securing thecap 40 to thevalve 36 to limit adjustment and maintain emissions calibration, and in a third position to releasably drivingly engage thevalve 36 to perform fuel flow adjustment. Thebody 82 also has a generally slottedrecess 88 in the face of the free end of thecap 40 for receiving an adjustment tool therein. - The
limiter arm 84 is an arcuate flanged projection which extends generally radially outwardly from thebody 82 for abutting against astop 90 carried by or operably associated with the carburetor to limit rotation to less than a complete revolution. The stop may be an adjacent valve shank, a cap mounted thereon (FIG. 7) 90, a fixed stop 90' projecting from the carburetor body (FIG. 8), a projection extending from thehousing 52,grommet 54, or engine 32 (not shown), or the like. Preferably, thearm 84 is set axially back from the cap face to allow adjustment without the surroundinggrommet 54 objectionably interfering with thearm 84. However, in applications where thecarburetor 34 is not enclosed by agrommet 54 orshroud 52, thearm 84 may be located anywhere along the axial length of thebody 82. Preferably, the angle subtended by theflange arm 84 is sufficient to limit the extent to which thevalve 36 can be rotated to fine tune the engine, or to conform with any required emissions regulation. Thearm 84 may have alocator indention 92 in its outer periphery to facilitate its use in an automatic cap feeding device. - As shown in FIG. 4, the
cap 40 may be mounted on thevalve 36 in a driving position with a first portion or circumferentiallycontinuous rib 94 within thepassage 86 adjacent the opening releasably drivingly engaging theknurled head 62. When releasably drivingly mounted in this position, thecap 40 and hence thevalve 36 can be rotated in unison to perform initial calibration adjustments. The mouth of thepassage 86 has achamfer 96 to facilitate entry of thevalve head 62 into therib 94. - Frequently, however, the
cap 40 is first placed on thehead 62 in the retainer position shown in FIG. 5 which allows thecap 40 to rotate freely with respect to thevalve 36 while retained thereon. When mounted in this position, thefirst segment 76 of thevalve head 62 is received in a circumferentiallycontinuous recess 98 in thepassage 86 with sufficient clearance to enable free rotation. Preferably, therib 94 of thepassage 86 and theshoulder 76 of thevalve 36 have an interference fit to retard removal from this freely rotating position. If desired, to releasably drivingly couple thecap 40 to theshank 60 of thevalve 36 for adjusting it, thecap 40 can be pushed slightly axially inwardly to engage thechamfer 96 with thesecond head segment 78 to adjust thevalve 36 by rotating thecap 40. When in this releasable driving position, thechamfer 102 and portion of thefirst rib 94adjacent chamfer 96 within thecap passage 86 may also releasably engage the knurled first 76 and second 78 head segments respectively. Upon releasing thecap 40, it will normally return to the retainer position where it can freely rotate relative to thevalve 36. - As shown in FIG. 6, to securely couple the
cap 40 to thevalve 36, thecap 40 may be pressed further axially onto thevalve 36 so thehead 62 frictionally engages and/or intermeshes with a circumferentially continuous rib in athird portion 100 of thepassage 86. To facilitate insertion of thehead 62 into thethird portion 100, it has aninclined camming surface 102. Preferably, therib 100 has an interference fit and when received in this position the material of the inner peripheral surfaces of the first 94 and third 100 portions deform around the knurls of thesecond head segment 78 to securely couple together thevalve 36 andcap 40 for simultaneous rotation and to resist removal of thecap 40. An interference fit between an adjacent shoulder of a circumferentiallycontinuous recess 104 at the end of thepassage 86 and the adjacent edge of thefirst segment 76 of thehead 62 securely locks thecap 40 to thevalve 36 further preventing removal. - FIGS. 19-21 illustrate a
protective shroud 150 for theneedle valves 36 & 38 and caps 40 & 42 carried by thecarburetor 48. Theshroud 150 is generally in the shape of a basket or cup with abottom wall 152, a preferablyintegral sidewall 154 lying closely adjacent the limiter caps, and an open end 156 opening generally axially of the limiter caps to provide access for adjustment thereof. To prevent tampering and prying with a tool on the assembled caps and valve heads, thesidewall 154 of the shroud extends axially over and beyond the caps and lies closely adjacent to the periphery of the caps. Preferably, in cross-section the sidewall is of generally oval configuration with opposedsemi-circular portions 158 inter-connected byparallel portions 160 which are spaced from and lie closely adjacent to the periphery of the limiter caps. Thebottom wall 152 has clearance holes 162 through which the shanks of the valves extend and in assembly is yieldably urged in firm engagement with a support surface 164 of the carburetor body by the compression springs 72. Preferably theshroud 150 is a one-piece metal stamping or a molded plastic part. - FIG. 22 illustrates a modified form of the shroud and carburetor assembly in which a shroud 150' is formed as an integral part of the body of the
carburetor 34. Typically the shroud 150' and carburetor are die cast as one part of a low melting temperature metal such as aluminum. - FIGS. 9-12 illustrate a second form of a needle valve 36' and a cap 40'. The needle valve 36' is essentially the same as
needle 36 except that the first head segment 76' has aslot 68 therein for receiving the blade of a tool, such as a screwdriver, to rotate the valve 36' and aperipheral cam surface 106. To facilitate insertion of a tool through the cap 40' to engage theslot 68 of the needle valve 36', thebody 82 has anaccess hole 108 through the free end thereof. In all other respects, the cap 40' has essentially the same construction ascap 40. - As shown in FIG. 9, the cap 40' can be disposed in a first position on the needle valve 36' where it is retained thereon while being freely rotatable relative to the valve 36' so that it does not drivingly engage it. As illustrated in FIG. 11, the cap 36' can be pushed slightly axially inward of this position, either manually or with a tool engaging slot 88' or an
arcuate relief indentation 89 inflange 84, to releasably drivingly engage thechamfer surface 96 with the adjacent end of thesecond head segment 78 to drivingly turn the valve 36' by rotating the cap 40'. If necessary, a portion of thefirst rib 94 adjacent thechamfer 96 may also releasably engage thesecond head segment 78 to facilitate adjusting the valve 36'. When released, the cap 40' will normally return to the retained position (FIG. 9) where it can freely rotate relative to the valve 36'. Alternatively, the valve can be directly adjusted by inserting a tool throughbore 108 and engagingslot 68. As shown in FIG. 12, the cap 40' can be pressed further axially onto the valve 36' to a second position where the valve 36' and cap 40' are securely coupled together to limit rotation of the valve 36'. If desired, fine adjustment may be made by using a tool to engage slot 88' orindention 89 in the cap orslot 68 in the first segment 76' of the valve head 62'. - FIGS. 13-15 illustrate a third form of the invention with needle valve 36' and
cap 40. Since thecap 40 has a closed free end with a drivingslot 88 therein, once thecap 40 is received on the needle valve 36', theslot 88 in the head 62' of the valve 36' cannot be directly engaged to rotate the valve 36'. - As shown in FIG. 13, in a first position the
cap 40 is retained on the valve 36' while being freely rotatable relative to the valve 36' and can be pushed slightly axially inward of this position to engage the chamferedportion 96 with the head 62' to drivingly turn the valve 36' by rotating thecap 40. As shown in FIG. 15, thecap 40 can be pushed further axially onto the valve 36' to a second position to couple and secure thecap 40 and valve 36' for rotation therewith to limit adjustment of the valve 36'. - A fourth form of the invention is shown in FIGS. 16-18 with a needle valve 36'' and a cap 40''. As shown in FIG. 17, the cap 40'' is releasably retained and freely rotates in a first position on the valve 36'' by the cooperation of a circumferentially continuous recess 98'' in the passage of the cap 40'' and a head 62'' on the free end of the valve 36''. The cap 40'' is retained on the head 62'' in the freely rotating position by the cooperation of the adjacent edge or shoulder of the recess 98'' which has a slight interference fit with the adjacent edge of the head 62''. As shown in FIG. 18, in a second position, the cap 40'' is securely coupled to the valve 36'' by frictional or intermeshing engagement of the head 62'' with a third portion 100'' of the passage to limit adjustment of the valve 36''. Insertion of the head 62'' into the inner rib 100'' is facilitated by a chamfer 102'' at the entrance thereto. As shown in FIG. 16, if desired, initially the cap 40'' can be releasably drivingly engaged with the head 62'' of the needle valve 36'' by pushing the shoulder of the first passage portion 94'' into engagement with the leading portion of the head 62''. The chamfer 96'' facilitates engaging the shoulder with the head 62''.
- A fifth form of the invention in shown in FIGS. 23-25 with
limiter caps main needle valves caps caps 110 & 112 in a predetermined relative circumferential or angular position with respect to the desired range of user adjustment of the needle valves (such as high end or low end of the range) before they are securely assembled in a limiter position on the valves, as shown in FIG. 25, they have cooperating detents 118 and 120 thereon. The detents project radially outwardly of the body of their cap and are axially disposed so that they overlap and abut when, as shown in FIG. 23, both of the caps are received in the first or retainer position on the valve shanks and, as shown in FIG. 25, thelimiter arm 84 or 84' of each cap bears on the other cap. This ensures a predetermined orientation of each limiter cap relative to the adjusted position of its needle valve so that when, as shown in FIG. 24, the caps are assembled in the limiter position on the valve shanks, they are in a predetermined desired orientation (high end or low end) relative to the range of user adjustment they permit for each needle valve. When the user initially rotates either cap, the detents resiliently yield and one slides over the other to permit adjustment of the associated valve within the range allowed by the limiter cap. Preferably, each cap and its detent are molded in one piece of a somewhat resilient plastic material such as nylon. - FIGS. 26-28 illustrate a suitable bit or
tool 122 for engaging and turning thevalves 114 & 116 when alimiter cap 110 & 112 is received thereon. The tool has asquare shank 124 which merges into aconical tip 126 at one end. As shown in FIG. 23 in use, the tool is inserted through the cap and thetip 126 is disposed in a chamferedblind bore 128 in the head of the valve for generally axially aligning the tool therein. A pair of opposed side faces 130 of the shank of the tool are slidably received between the side faces 132 of theslot 68 in the head for driving engagement therewith to rotate the valve by rotating or turning the tool. - FIG. 29 illustrates modified limiter caps 110', 112' having a
thin interconnecting web 134 in lieu of the detents 118 and 120 of the limiters cap 110 and 112. Preferably, limiter caps 110' & 112' are molded together along with theweb 134 in one piece preferably of a plastic material. The caps interconnected by the web are installed onvalves caps web 134 is broken and each needle valve can be adjusted within the predetermined range provided by the limiter caps. - A seventh form of the invention is illustrated in FIGS. 30-32 in which a pair of limiter caps 140 & 140' are received on idle and
main needle valves 114 & 116 and each disposed in a predetermined circumferential or angular orientation relative to its needle valve by the cooperation of a compression andtorsion spring 142 therewith. To orient the cap, the spring has at one end a radially inwardly projectingtang 144 which in assembly is received in theslot 68 in the head of the valve and at the other end anaxially projecting tang 146 which in assembly is received in a complementaryblind hole 148 in the end wall of the cap. The only difference between thecaps 140 & 140' is the arcuate location of theholes 148 which are relatively diametrically opposed. However, if desired, the holes could be in the same location for both caps and the spring tangs 144 would be received in relatively opposite ends of thevalve head slots 68. - When received in the first or retainer position on a valve, the cap can be disposed in any desired predetermined circumferential orientation relative to its valve by selecting and designing the desired circumferential or angular orientation of the
spring tang 144 & 146 to each other and to theslot 68 in the valve and thehole 148 in the cap. For example, as shown in FIG. 32, these parameters can be selected and adjusted so that after any fine tuning adjustment of the valves, the caps will be oriented in the retainer position so that thelimiter arm 84 or 84' of each cap bears on the body of the other cap when, as shown in FIG. 32, the caps are to be securely assembled in the limiter position on the valves. - In use, the caps may be pressed onto the
valve 36 to a position where thefirst segment 76 of thevalve head 62 engages with therib 94 of thecap passage 86. While in this position, thevalve 36 may be adjusted, such as during flow testing or final calibration. To adjust thevalve 36, torque is applied to thecap 40 through an adjustment tool engaging thecap recess 88. - Usually, however, the
cap 40 is initially mounted to and carried by thevalve 36 in the freely rotating retainer position. Advantageously, thecap 40 may be attached in this retainer position any time after flow testing so that thecarburetor 34 may be shipped or other assembly operations performed without inadvertently disturbing the valve calibration. For example, it may be desirable to assemble thegrommet 54,shroud 52 or both after attaching thecap 40 in this retainer position. During this stage of assembly, fine adjustment of fuel flow to tune an actual specific engine in operation into compliance with emissions requirements may be simply and easily achieved. - To fine tune fuel flow while in the freely rotating retainer position, the slotted
cap face 88 is engaged by an adjustment tool and a sufficient axially inward force is applied against thecap 40 causing thefirst passage section 94 to releasably engage the knurledsecond segment 78 enabling rotation in unison. While engaged, thecap 40 andvalve 36 may be rotated until engine exhaust emissions fall within the desired range. If thelimiter arm 84 abuts against astop 90 and more adjustment is needed, the applied force can be withdrawn releasing thecap 40 from frictional engagement and thearm 84 freely rotated away from thestop 90 without rotating thevalve 36 to provide an additional range of adjustment. To further adjust thevalve 36, sufficient force may be once again applied to engage thehead 62 and a torque applied to rotate thecap 40 andvalve 36 in unison. In this manner, thecap 40 may be used to ratchet thevalve 36 in either direction to provide an unlimited range of adjustment. However, if thecap opening 108, emissions calibration may also be performed at this assembly stage simply by directly engaging thevalve - Before securing a cap to a valve, the cap (other than cap 110', 112') is freely rotated to easily and accurately orient the
limiter arm 84 or 84' relative to the calibrated valve and stop member. To stay within emissions restrictions while allowing sufficient end user adjustment to keep the engine efficiently operating, the limiter arm position, arm flange width and stop configuration and position are selected, designed and constructed as will be apparent to skilled persons and need not be described in further detail. - The
caps 110 & 112, 110'& 112' and 140 & 140' may be readily circumferentially oriented relative to their completely calibrated valves, stop members and the desired allowable range of adjustment by the end user by their detents 118 & 120,web 132, or cooperating springs 142. For example, thecaps web 134 and for thecaps 140 & 140' by cooperation by thesprings 142. It will be apparent to skilled persons that the positions of the arms of these caps relative to their associated detents, web or springs can also be selected, designed and constructed to position them at the low end or at an intermediate position in the desired range of adjustment by the end user, and hence need not be described in further detail. - Once the
limiter arm 84 or 84' is circumferentially or angularly positioned on the valve, a force is applied to axially move the cap into firm frictional engagement with theknurled head 62 or 62' preventing removal and tampering. Optionally, valve adjustment may be performed after final cap assembly if the allowable range of rotation is sufficient to properly calibrate fuel flow. In this final position, valve (36, 36', 114 or 116) rotation in either direction is restricted by thearm 84 or 84' abutting with astop 90 or 90' preventing emissions-violating overadjustment by an end user while enabling a sufficient adjustment range to fine tune engine performance in response to a wide range of operating conditions. - Preferably, the limiter caps are of one piece, unitary construction for simpleness and ease of manufacture, and are constructed from a generally homogeneous material such as Zytel® or Minlon®, nylon formulations which are both registered trademarks of E. I. Du Pont De Nemours and Company, a different nylon formulation, Delrin® (a POM thermoplastic) also a Du Pont material, or another high temperature thermoplastic material. A cap constructed of any of these materials is strong and resilient and able to deform around the knurls of the valve head to more positively frictionally secure the cap to the valve while resisting brittle fracture if tampered with. More generally, however, the caps could also be composed of a phenolic, polyurethane, polyacrylic, rubber or some other plastic material.
- While the present invention has been disclosed in connection with the preferred embodiments thereof, it should be understood that there may be other embodiments which fall within the spirit and scope of the invention and that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the following claims.
Claims (34)
- A cap for limiting adjustment of fuel flow in a carburetor by a valve having a rotatable shank with a head end projecting from the carburetor comprising: a body having a passage therein constructed and arranged to be telescopically received over the head end of the shank of the valve, retainer means in said passage and constructed and arranged to retain said body in a first telescoped position on the shank with said body being freely rotatable relative to the shank, engagement means in said passage and constructed and arranged to engage with the head end when said body is telescoped over the shank and in a second position axially spaced from said first position to couple the shank with said body so that the shank and said body can rotate only in unison when said body is in said second position, an arm fixed to said body and projecting generally radially thereof and constructed and arranged to limit the extent of rotation of the shank to less than one revolution when said body is in said second position by engagement of said arm with at least one stop operably associated therewith, orienting means operably associated with said body and constructed and arranged to angularly orient said arm of said cap relative to the shank of the valve and the one stop operably associated with said arm when the cap is in said first position on the shank and while the cap is being moved from the first position to the second position on the shank to couple the shank with the body of the cap, whereby when said body is telescoped over the shank and in said first position the shank can rotate relative to said body and when in said second position said body and the shank can only be rotated in unison and said arm is engagable with at least one stop to limit the rotation of the shank and cap to less than one complete revolution to thereby limit adjustment of the valve.
- The cap of claim 1 wherein said orienting means comprises a detent carried by said body, projecting radially outwardly thereof, and constructed and arranged to cooperate with a complementary detent of another cap received on a rotatable shank of another valve when said detent and another detent are operably engaged.
- The cap of claim 1 wherein said orienting means comprises a relatively thin web connected to said cap and to another cap received on a rotatable shank of another valve.
- The cap of claim 1 wherein said orienting means comprises a spring received in the cap with one end operably connected to the cap and the other end operably connected with the head of the shank of the valve.
- The cap of claim 1 wherein said orienting means comprises a spring received in the cap and having one end received in a complementary hole in the cap and the other end received in a groove in the head of the shank of the valve.
- The cap of claim 1 wherein said passage extends completely through said body and is constructed and arranged to permit an adjustment tool to be disposed therein and engaged with a recess in the head end of the shank and which has a non-circular cross-section for rotating the shank relative to the carburetor when the cap is telescopically received on the shank.
- The cap of claim 1 wherein said passage extends completely through said body and is constructed and arranged to permit an adjustment tool to be disposed therein and engaged with a slot in the head end of the shank for rotating the shank relative to the carburetor when the cap is telescopically received on the shank.
- The cap of claim 1 which also comprises a recess in an end of said body, having a non-circular cross-section and constructed and arranged to receive a tool therein for rotating the cap relative to the carburetor.
- The cap of claim 1 which also comprises a recess in an end of said body, having a non-circular cross-section and constructed and arranged to receive a tool therein for rotating the cap relative to the carburetor, and wherein when said body is telescoped over the shank and in a third position axially displaced from said first and second positions, said body drivingly engages the shank so that rotating said body also rotates the shank in unison therewith to adjust fuel flow of the carburetor.
- The cap of claim 1 which also comprises a recess in an end of said body, having a non-circular cross-section and constructed and arranged to receive a tool therein for rotating the cap relative to the carburetor, and drive means in said passage constructed and arranged to engage with the shank for drivingly rotating the shank in unison with rotation of said body when said body is telescoped over the shank and in a third position thereon axially spaced from both said first and second positions, whereby when said body is in the third position rotation of said cap by a tool disposed in said recess of said body drivingly rotates the shank of the valve to adjust fuel flow of the carburetor.
- The cap of claim 1 which also comprises a locator notch in the outer periphery of said arm for facilitating the location and orientation of the cap for assembly.
- The cap of claim 1 wherein at least one stop carried by the carburetor comprises a shank of another fuel flow adjusting valve of the carburetor which projects into the arcuate path of rotation of said arm of said body at least when said body is in its second position.
- The cap of claim 1 wherein at least one stop carried by the carburetor comprises a body of another limiter cap telescopingly received over a shank of another fuel flow adjusting valve of the carburetor which projects into the arcuate path of rotation of said arm of said body at least when said body is in its second position.
- The cap of claim 1 wherein said body, arm and orienting means are of one homogeneous piece of a plastic material which is at least somewhat resilient.
- The cap of claim 1 which also comprises a shroud carried by the carburetor, encircling the valves and the caps received thereon, spaced from and lying closely adjacent to the periphery of the caps, extending axially outwardly of the caps, and opening generally axially outwardly to provide access to the free ends of the caps.
- The cap of claim 1 wherein said body and arm are of one homogeneous piece of a nylon or polyxoymethylene plastic material which is at least somewhat resilient.
- The cap of claim 1 wherein said engagement means is constructed and arranged to have a press fit with the shank when said body is in said second position on the shank.
- The cap of claim 1 which also comprises a recess in an end of said body, having a non-circular cross-section and constructed and arranged to receive a tool therein for rotating the cap relative to the carburetor, and wherein when said body is telescoped over the shank and in a third position axially spaced from said first and second positions, drive means in said passage for engaging the shank for rotating said body and the shank in unison therewith when in said third position to adjust fuel flow of the carburetor, latching means in said passage and constructed and arranged to latch with the shank when said body is telescoped over the shank and in said second position to retard removal of the cap from the valve.
- For a carburetor having a valve for adjusting fuel flow by rotating a shank of the valve projecting from the carburetor, an adjustment limiting apparatus comprising a body having a passage therein constructed and arranged to be telescopically received over an end of the shank, a recess on one of the shank and in said passage of said body, a projection on the other of said shank and in said passage of said body, at least one of said recess and said projection being substantially circumferentially continuous, said recess and projection being constructed and arranged so that when said body is telescoped over the shank in a first position, said projection is received in said recess so that the shank can be rotated relative to said body and said body is retained on the shank, a head on the shank, an engagement portion in the passage of said body which engages with said head when said body is received on the shank in a second position axially spaced from said first position to couple said body to the shank for rotation only in unison therewith, an arm fixed to said body and projecting generally radially thereof and constructed and arranged to limit the extent of rotation of the shank to less than one complete revolution at least when said body is in said second position by engagement of said arm with at least one stop carried by the carburetor and projecting into the arcuate path of rotary movement of said arm, orienting means operably associated with said body and constructed and arranged to angularly orient said arm of said cap relative to the shank of the valve and the one stop operably associated with said arm when the cap is in said first position on the shank and while the cap is being moved from the first position to the second position on the shank to couple the shank with the body of the cap, whereby when said body is telescoped over the shank and in said first position, the shank can rotate relative to the body while retained thereon and when in said second position the shank and said body can be rotated only in unison and said arm is engagable with at least one stop to limit the rotation of the shank and said body to less than one complete revolution to thereby limit adjustment of the valve.
- The cap of claim 19 wherein said orienting means comprises a detent carried by said body, projecting radially outwardly thereof, and constructed and arranged to cooperate with a complementary detent of another cap received on a rotatable shank of another valve when said detent and another detent are operably engaged.
- The cap of claim 19 wherein said orienting means comprises a relatively thin web connected to said cap and to another cap received on a rotatable shank of another valve.
- The cap of claim 19 wherein said orienting means comprises a spring received in the cap with one end operably connected to the cap and the other end operably connected with the head of the shank of the valve.
- The cap of claim 19 wherein said orienting means comprises a spring received in the cap and having one end received in a complementary hole in the cap and the other end received in a groove in the head of the shank of the valve.
- The apparatus of claim 19 wherein said head has a knurled surface thereon engagable with said retainer portion in said passage of said body when in said second position, and said body, arm, and orienting means are of a one-piece homogeneous plastic material which is at least slightly resilient.
- The apparatus of claim 19 wherein said passage extends completely through said body and is constructed and arranged to permit an adjustment tool to be disposed therein and engaged with a recess in the head end of the shank and which has a non-circular cross-section for rotating the shank relative to the carburetor when said body is telescopically received on the shank.
- The apparatus of claim 19 which also comprises a recess in an end of said body having a non-circular cross-section and constructed and arranged to receive a tool therein for rotating said body relative to the carburetor, drive means in said passage constructed and arranged to engage with the shank for drivingly rotating the shank in unison with rotation of said body when said body is telescoped over the shank and in a third position thereon axially spaced from both said first and said second positions, whereby when said body is in said third position rotation of said body by a tool disposed in said recess of said body drivingly rotates the shank to adjust fuel flow of the carburetor.
- The apparatus of claim 19 wherein the stop carried by the carburetor comprises a shank of another fuel flow adjusting valve of the carburetor which projects into the arcuate path of rotation of said arm of said body at least when said body is in said second position on the shank.
- The apparatus of claim 19 wherein the stop carried by the carburetor comprises a body of another cap telescopingly received over a shank of another fuel flow adjusting valve of the carburetor which projects into the arcuate path of rotation of said arm of said body at least when said body is in its second position.
- The apparatus of claim 19 wherein said head and said engagement portions are constructed, arranged, and dimensioned to have a press fit.
- A method of adjusting the fuel flow of a carburetor and limiting further adjustment thereof comprising:(a) providing a carburetor having at least one valve for adjusting fuel flow by rotating a shank of the valve projecting from the carburetor,(b) placing the carburetor in a test stand and rotating the shank to adjust fuel flow to a desired predetermined valve,(c) providing a limiter cap having a body with a passage therein constructed and arranged to be telescopically received over an end of the shank, the body having retainer means in the passage constructed and arranged to retain the body in a first position on the shank with the body being freely rotatable relative to the shank, engagement means in the passage and constructed and arranged to engage with the shank when the body is telescoped over the shank and in a second position axially spaced from the first position to couple the shank with the body so that the shank and body can rotate only in unison when the body is in the second position, an arm fixed to the body and projecting generally radially therefrom and constructed and arranged to limit the extent of rotation of the shank to less than one revolution when the body is telescoped over the shank and in the second position by engagement of the arm with at least one stop carried by the carburetor, and orienting means operably associated with said body and constructed and arranged to angularly orient said arm of said cap relative to the shank of the valve and the one stop operably associated with said arm when the cap is in said first position on the shank and while the cap is being moved from the first position to the second position on the shank to couple the shank with the body of the cap,(d) positioning the cap on the shank with the body telescoped over the shank and in the first position thereof on the shank,(e) mounting the carburetor on an engine with which it will be utilized,(f) thereafter while operating the engine making any further needed adjustment of the valve by rotating the shank to fine tune fuel flow to optimize predetermined operating parameters of the engine,(g) utilizing the orienting means to angularly orient the cap while in the first position on the shank in a predetermined position relative to the fine tuned fuel flow position of the shank resulting from step (e), and(h) after step (g) moving the body to the second position on the shank to thereby limit the extent of any subsequent adjustment of the valve by the arm of the cap bearing on at least one stop carried by the carburetor and disposed in the arcuate path of movement of the arm at least while the cap is in the second position on the shank.
- The method of claim 30 which also comprises after the cap is disposed in the first position on the shank and before the fine tuning of the carburetor, the steps of disposing a shroud around the carburetor which has an access hole therein spaced from and generally axially aligned with the shank when the shroud is disposed in a predetermined position and thereafter without removing the shroud steps (f), (g) and (h) are performed.
- The method of claim 30 which also comprises engagement means in the passage of the body and constructed and arranged to releasably engage the shank when the body is telescoped over the shank and in a third position axially spaced from the first and second positions to releasably couple the shank with the body so that the shank and body can rotate in unison when the body is in the third position, moving the body over the shank to the third position, rotating both the cap and valve in unison to adjust fuel flow until the arm of the body abuts against at least one stop carried by the carburetor, moving the cap to the first position on the shank, freely rotating the cap relative to the valve to rotate the arm away from at least one stop carried by the carburetor, moving the cap to the third position on the shank, rotating the cap and valve in unison to adjust fuel flow, and thereafter moving the cap to the second position on the shank.
- The method of claim 30 wherein the head of the shank has a non-circular recess therein opening generally axially thereof and in performing step (f) an adjustment tool is inserted generally axially through the free end of the cap and into driving engagement with the recess in the head of the valve to make any further needed adjustment of the valve by rotating the shank of the valve while the cap is received in the first position thereon.
- The method of claim 30 which also comprises before the cap is disposed in the first position on the shank and before the fine tuning of the carburetor, the steps of disposing a shroud around the valve shank which has an access opening therein spaced from and generally axially aligned with the shank when the shroud is disposed on the carburetor, thereafter inserting the cap through the access opening and disposing the cap in the first position on the shank and within the shroud, and thereafter without removing the shroud steps (f), (g) and (h) are performed.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US949895 | 1992-09-23 | ||
US07/949,895 US5236634A (en) | 1992-09-23 | 1992-09-23 | Carburetor needle valve adjustment limiter cap and method of adjusting fuel flow |
US08/106,410 US5322645A (en) | 1992-09-23 | 1993-08-13 | Carburetor needle valve adjustment limiter cap and method of use |
US106410 | 2005-04-14 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0589405A1 true EP0589405A1 (en) | 1994-03-30 |
EP0589405B1 EP0589405B1 (en) | 1997-07-09 |
Family
ID=26803635
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19930115159 Expired - Lifetime EP0589405B1 (en) | 1992-09-23 | 1993-09-20 | Carburettor needle valve adjustment limiter cap |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0589405B1 (en) |
JP (1) | JP2578571B2 (en) |
DE (1) | DE69311995T2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996012884A1 (en) * | 1994-10-19 | 1996-05-02 | Wci Outdoor Products, Inc. | Fuel mixture limitation device |
DE19833541A1 (en) * | 1998-07-25 | 2000-01-27 | Stihl Maschf Andreas | Carburetor for internal combustion engine is portable, manually controlled work apparatus, such as motor chain saw, has suction channel in housing and fuel channel issuing into suction channel |
EP1087117A2 (en) * | 1999-09-27 | 2001-03-28 | Walbro Japan, Inc. | Carburetor valve adjustment limiter cap assembly |
CN112539120A (en) * | 2015-11-06 | 2021-03-23 | 沃尔布罗有限责任公司 | Carburetor air-fuel mixture adjustment assembly and tool |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108105460B (en) * | 2017-12-20 | 2019-05-28 | 北京卫星环境工程研究所 | Spacecraft GFDV type adds valve accurate limiting switching device |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3618906A (en) * | 1967-08-18 | 1971-11-09 | Ford Motor Co | Device and process for limiting idling fuel in carburetors |
FR2291362A1 (en) * | 1974-11-15 | 1976-06-11 | Sibe | IMPROVEMENTS TO SCREW ADJUSTING DEVICES FOR CARBURETORS |
FR2352955A2 (en) * | 1974-11-15 | 1977-12-23 | Sibe | Protective cap for carburettor slow running jet screw - has snap on plastic sleeve placed over screw to prevent tampering with setting |
US5055238A (en) * | 1989-06-30 | 1991-10-08 | Shinagawa Diecast Industrial Corp. | Diaphragm carburetor |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS53139897A (en) * | 1977-05-10 | 1978-12-06 | Asahi Chemical Ind | Oil agent composition and treating of thermoplastic synthetic fiber for rubber reinforcing by said composition |
JPS5443322A (en) * | 1977-09-12 | 1979-04-05 | Tlv Co Ltd | Steam trap |
JPS5516133U (en) * | 1978-07-17 | 1980-02-01 | ||
JPS6018132A (en) * | 1983-07-11 | 1985-01-30 | 鈴木 四郎 | Automatic chicken grilling spit |
-
1993
- 1993-09-20 EP EP19930115159 patent/EP0589405B1/en not_active Expired - Lifetime
- 1993-09-20 DE DE1993611995 patent/DE69311995T2/en not_active Expired - Fee Related
- 1993-09-22 JP JP5236164A patent/JP2578571B2/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3618906A (en) * | 1967-08-18 | 1971-11-09 | Ford Motor Co | Device and process for limiting idling fuel in carburetors |
FR2291362A1 (en) * | 1974-11-15 | 1976-06-11 | Sibe | IMPROVEMENTS TO SCREW ADJUSTING DEVICES FOR CARBURETORS |
FR2352955A2 (en) * | 1974-11-15 | 1977-12-23 | Sibe | Protective cap for carburettor slow running jet screw - has snap on plastic sleeve placed over screw to prevent tampering with setting |
US5055238A (en) * | 1989-06-30 | 1991-10-08 | Shinagawa Diecast Industrial Corp. | Diaphragm carburetor |
US5055238B1 (en) * | 1989-06-30 | 1994-01-18 | Shinagawa Diecast Industrial Corp. |
Non-Patent Citations (1)
Title |
---|
"Alimentation", REVUE TECHNIQUE AOTOMOBILE, vol. 32, no. 372, 1 November 1977 (1977-11-01), BOULOGNE-BILLANCOUR FR, pages 136 - 137 * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996012884A1 (en) * | 1994-10-19 | 1996-05-02 | Wci Outdoor Products, Inc. | Fuel mixture limitation device |
DE19833541A1 (en) * | 1998-07-25 | 2000-01-27 | Stihl Maschf Andreas | Carburetor for internal combustion engine is portable, manually controlled work apparatus, such as motor chain saw, has suction channel in housing and fuel channel issuing into suction channel |
DE19833541C2 (en) * | 1998-07-25 | 2000-07-13 | Stihl Maschf Andreas | Fuel adjusting screw on a carburetor for an internal combustion engine |
US6234458B1 (en) | 1998-07-25 | 2001-05-22 | Andreas Stihl Ag & Co. | Carburetor with secured control screw |
EP1087117A2 (en) * | 1999-09-27 | 2001-03-28 | Walbro Japan, Inc. | Carburetor valve adjustment limiter cap assembly |
EP1087117A3 (en) * | 1999-09-27 | 2002-07-10 | Walbro Japan, Inc. | Carburetor valve adjustment limiter cap assembly |
US6467757B1 (en) | 1999-09-27 | 2002-10-22 | Walbro Japan, Inc. | Carburetor valve adjustment limiter cap assembly |
CN112539120A (en) * | 2015-11-06 | 2021-03-23 | 沃尔布罗有限责任公司 | Carburetor air-fuel mixture adjustment assembly and tool |
CN112539120B (en) * | 2015-11-06 | 2022-08-02 | 沃尔布罗有限责任公司 | Carburetor air-fuel mixture adjustment assembly and tool |
Also Published As
Publication number | Publication date |
---|---|
EP0589405B1 (en) | 1997-07-09 |
JPH06200826A (en) | 1994-07-19 |
DE69311995T2 (en) | 1997-11-06 |
DE69311995D1 (en) | 1997-08-14 |
JP2578571B2 (en) | 1997-02-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5322645A (en) | Carburetor needle valve adjustment limiter cap and method of use | |
US5753148A (en) | Carburetor needle valve adjustment limiter cap apparatus and method of adjusting fuel flow | |
US5984281A (en) | Carburetor needle valve and limiter cap installation and adjustment apparatus | |
US5707561A (en) | Tamper resistant carburetor needle valve adjustment limiter | |
US5635113A (en) | Carburetor adjustment screw apparatus | |
US7097165B1 (en) | Carburetor fuel adjustment and limiter assembly | |
US5955007A (en) | Carburetor fuel adjusting device | |
US5667734A (en) | Carburetor with regulating valve limiting device | |
US5525267A (en) | Tamper resistant limit cap | |
EP0589405B1 (en) | Carburettor needle valve adjustment limiter cap | |
CN110774231A (en) | Manually guided working device and method for assembling an anti-vibration element of a manually guided working device | |
US11293380B2 (en) | Charge forming device with adjustable valve limiter | |
US4239710A (en) | Device for checking random adjustment of adjustable parts of carburetor | |
US5630965A (en) | Low force limit device | |
CA2430016C (en) | Tamper resistant carburetor mixture needles | |
US5507084A (en) | Removal tool | |
US11761403B2 (en) | Charge forming device with tamper resistant adjustable valve | |
US6467757B1 (en) | Carburetor valve adjustment limiter cap assembly | |
JPH07286560A (en) | Operation limiting device for fuel adjusting needle valve of carburetor | |
IE75665B1 (en) | An adjustment screw apparatus | |
JPH04116663U (en) | Fuel injection pump camshaft fixing jig |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE GB IT SE |
|
17P | Request for examination filed |
Effective date: 19940516 |
|
17Q | First examination report despatched |
Effective date: 19950303 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE GB IT SE |
|
REF | Corresponds to: |
Ref document number: 69311995 Country of ref document: DE Date of ref document: 19970814 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19990902 Year of fee payment: 7 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20000920 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20000920 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 20030919 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20031031 Year of fee payment: 11 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20040921 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20050401 |
|
EUG | Se: european patent has lapsed | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 20050920 |